Method and system for evaluating the distribution of an absorbent material in an absorbent article

ABSTRACT

A system for imaging a distribution of an absorbent material within an absorbent article. The system includes a radiation source and a detector positioned such that the absorbent article is situated between the radiation source and the detector. The absorbent article includes an absorbent material having a spatial distribution within the absorbent article. Infrared radiation within a particular wavelength range (e.g., 3 μm to 3.2 μm) is more likely to be absorbed by the absorbent material than by other materials within the absorbent article. The radiation source is configured to generate infrared radiation incident on the absorbent article. The detector is configured to detect a quantity of the infrared radiation within the particular wavelength range that was transmitted through the absorbent article. The radiation source is further configured to generate data indicative of the spatial distribution of the absorbent material based on the detected quantity of the infrared radiation.

FIELD OF THE INVENTION

This disclosure relates generally to the field of absorbent articlesand, more particularly, to methods and systems for evaluating thedistribution of an absorbent material in an absorbent article.

BACKGROUND OF THE INVENTION

An important component of absorbent articles such as diapers, sanitarynapkins, pantiliners, incontinent pads, breast pads, perspiration pads,an the like, is an absorbent core structure that includes absorbentmaterials, such as water-absorbing polymeric particles, typicallyhydrogel-forming water-swellable polymers, also referred to as absorbentgelling material (“AGM”), or super-absorbent polymers (“SAP”). Theseabsorbent materials ensure that large amounts of fluids, e.g. urine, canbe absorbed by the article during its use and locked away, thusproviding low rewet and good skin dryness, thereby reducing wearerdiscomfort.

Different absorbent articles may be designed with different spatialpatterns, or distributions, of AGM within their absorbent corestructures, depending, for instance, on the nature and/or the intendeduse of the absorbent articles. For example, diapers intended for boysmay have a different distribution of AGM than those intended for girls.Differences in the distributions of AGM may include variations in theshapes of AGM distribution (e.g., rectangular, elliptical, and so on),discrepancies in the overall densities of AGM (or densities inparticular regions) and/or in the density transitions between differentregions of the absorbent core structure. Differences in thedistributions of AGM may further include differences in the absolutequantities of AGM, in the bias, or evenness, of the AGM (e.g., quantityof AGM in the front portion of the absorbent article relative to theback portion). A variety of other factors may contribute to thedifference in the distribution of AGM in different absorbent articles,including the amount of AGM laminate, AGM scatter, etc.

Because different absorbent articles may be designed with differentspatial distributions of AGM within their absorbent core structures, itis often desired to evaluate the distribution of AGM in a particularabsorbent article. For example, the distribution of AGM may be evaluatedfor quality control purposes during manufacturing (e.g., to ensure thatabsorbent articles are produced to meet or exceed certain requirements).Additionally, or alternatively, evaluation of the distribution of AGMmay be performed in a product and/or process development context, forinstance, to develop more optimal techniques for distributing AGM withina particular type of absorbent article.

In the past, distribution of AGM within a given absorbent article couldbe evaluated in a number of ways. For example, quality control personnelcould physically feel for a presence or an absence of AGM in differentregions of the absorbent article with their fingers and roughly estimatethe distribution of AGM. In some cases, the absorbent article could bepassed through some sort of a capacitive sensor, and the amount of AGMin different portions of the absorbent article could be approximatedbased on the capacitance of the different portions.

The absorbent article could also be cut open, and various sections ofthe cut-up absorbent article could be examined under a microscope toidentify the distribution of AGM in the various sections. The varioussections could also be weighed, and the quantity of AGM in each sectioncould be estimated based on the respective weights of the sections.

Traditional methods of evaluating the distribution of AGM in anabsorbent article present a number of problems. Results yielded by thesemethods are typically imprecise, inconsistent, or both. For example, thetest that involves physically feeling for the presence or absence of AGMwith fingers may yield different results based on who is doing thetesting. Furthermore, given that a granule of AGM is roughly the samesize as a grain of salt, a person's fingers may not be sensitive enoughto provide a sufficiently accurate estimation. The same may be saidregarding capacitive sensors.

With regard to methods that involve cutting the absorbent article intoseveral sections, these methods may provide information regardingdistribution of AGM among the different sections, but they might notprovide helpful information regarding the distribution of AGM within theindividual sections. For example, if the absorbent article is cut intothree sections, and each section has roughly the same weight, it doesnot necessarily mean that the AGM is distributed uniformly within eachsection. Furthermore, cutting up the absorbent article may disrupt theoriginal distribution of AGM and, thus, make it difficult, if notimpossible, to determine the original AGM distribution. Still further,cutting up the absorbent article typically means eliminating thatabsorbent article from production, and that may be undesirable, forexample, in the context of an inline manufacturing process.

SUMMARY OF THE INVENTION

The present disclosure provides techniques for evaluating thedistribution of an absorbent material in an absorbent article.

In one embodiment, a system for imaging a distribution of an absorbentmaterial within an absorbent article includes a radiation source and adetector. The radiation source and the detector are positioned such thatthe absorbent article is situated between the radiation source and thedetector. The absorbent article includes an absorbent material (e.g.,absorbent gelling material (AGM)) having a spatial distribution withinthe absorbent article. Infrared radiation within a particular wavelengthrange (e.g., 3 μm to 3.2 μm) is more likely to be absorbed by theabsorbent material than by other materials within the absorbent article.

The radiation source is configured to generate infrared radiationincident on the absorbent article. The detector is configured to detecta quantity of the infrared radiation within the particular wavelengthrange generated by the radiation source that was transmitted throughdifferent regions of the absorbent article. The radiation source isfurther configured to generate data indicative of the spatialdistribution of the absorbent material based on the detected quantity ofthe infrared radiation corresponding to the different regions of theabsorbent article.

In various implementations, one or more of the following features may beincluded. The absorbent article may be an assembled product or apreassembled product. The absorbent article may be a diaper, a sanitarynapkin, a pantiliner, an incontinent pad, a breast pad, a perspirationpad, etc.

The radiation source may include multiple light sources configured totransmit the infrared radiation, wherein at least one of the multiplelight sources is a tungsten-halogen bulb. The radiation source mayfurther include a diffuser configured to diffuse the infrared radiationtransmitted by the multiple light sources to produce a substantiallyuniform radiation pattern across the absorbent article.

The detector may include a mid wave infrared camera capable of detectinginfrared radiation in the particular wavelength range. The detector mayfurther include a filter that substantially blocks infrared radiationoutside of the particular wavelength range.

The detector may be further configured to generate an absorbent materialdistribution image representing the spatial distribution of theabsorbent material within the absorbent article based on the dataindicative of the spatial distribution of the absorbent material withinthe absorbent article. A color depth within a given region in theabsorbent material distribution image may be indicative of aconcentration of the absorbent material in the corresponding region ofthe absorbent article.

The absorbent material distribution image may be a binary imageincluding a first color and a second color, the first color representingpresence of an absorbent granule and the second color representingabsence of the absorbent granule. The absorbent material distributionimage may also be a grayscale image, where darker grayscale levelsrepresent a higher concentration of absorbent granules and lightergrayscale levels represent a lower concentration of absorbent granules.

In another embodiment, a method for evaluating a distribution of anabsorbent material within an absorbent article includes using infraredimaging to generate image data, where the image data represents aspatial distribution of an absorbent material within an absorbent coreof the absorbent article. The method further includes transforming theimage data into one or more attribute values related to one or moreattributes of the spatial distribution of the absorbent material. Themethod further includes representing the one or more attribute values asoutput.

In various implementations, one or more of the following features may beincluded. For example, the method may further include determining aquality of the absorbent article based on the one or more attributevalues.

The attributes of the spatial distribution may include, by way ofexample, a shape of the spatial distribution formed by the absorbentmaterial, a pattern of the spatial distribution formed by the absorbentmaterial, a quantity of the absorbent material within the absorbentcore, a density of the absorbent material within the absorbent core, anevenness of the spatial distribution, a location of one or more densitytransitions within the spatial distribution, a presence of absorbentmaterial laminate, and the presence of islands of absorbent material.

Determining the quality of the absorbent article may include determininga disparity between the determined one or more attributes of the spatialdistribution of the absorbent material and a corresponding one or moredesired attributes of the spatial distribution of the absorbentmaterial.

In another embodiment, a method of evaluating quality of an absorbentmaterial includes using infrared imaging to generate data indicative ofan absorbance of infrared radiation within a particular wavelength range(e.g., 3 μm to 3.2 μm) incident on a target article. The target articleincludes a monolayer of absorbent material substantially covering asurface of the target article. The infrared radiation within theparticular wavelength range is more likely to be absorbed by theabsorbent material than by other materials within the target article.The method further includes using infrared imaging to generate datarelated to an absorbance of infrared radiation within the particularwavelength range incident on an absorbent core of an absorbent article.The method further includes determining a quality of the absorbentarticle by comparing a disparity between the data related to theabsorbance of infrared radiation within the particular wavelength rangeincident on the target article and the data related to the absorbance ofinfrared radiation within the particular wavelength range incident onthe absorbent core of the absorbent article.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter that is regarded as thepresent invention, it is believed that the invention will be more fullyunderstood from the following description taken in conjunction with theaccompanying drawings. Some of the figures may have been simplified bythe omission of selected elements for the purpose of more clearlyshowing other elements. Such omissions of elements in some figures arenot necessarily indicative of the presence or absence of particularelements in any of the exemplary embodiments, except as may beexplicitly delineated in the corresponding written description. None ofthe drawings are necessarily to scale.

FIG. 1A is a partial aerial view of an the example absorbent article;

FIG. 1B is a partial cross-section view of an example absorbent article;

FIG. 2 is a block diagram of an example AGM distribution evaluationsystem;

FIG. 3A illustrates an example standalone AGM distribution imagingsystem;

FIG. 3B illustrates an example inline AGM distribution imaging system;

FIG. 4 is a block diagram of an example radiation source;

FIG. 5 is a block diagram of an example detector;

FIG. 6 is a block diagram of an example AGM distribution imageprocessing system 640.

FIG. 7 is a flow diagram illustrating an example method for processingAGM distribution image data;

FIG. 8A is a partial aerial view of an example absorbent article with anAGM monolayer;

FIG. 8B is a partial cross-section view of an example absorbent articlewith an AGM monolayer;

FIG. 9 is a flow diagram illustrating an example method for evaluatingthe AGM monolayer of an absorbent article; and

FIG. 10 illustrates an example target article that may be used toevaluate an AGM monolayer.

Like reference numbers and designations in the various drawings indicatelike elements. Furthermore, when individual elements are designated byreferences numbers in the form Nn, these elements may be referred to inthe collective by N. For example, FIGS. 2A and 2B illustrate example AGMdistribution imaging systems 200 a and 200 b, respectively, that may bereferred to collectively as AGM distribution imaging systems 200.

DETAILED DESCRIPTION OF THE INVENTION

Although the following text sets forth a detailed description ofnumerous different embodiments, it should be understood that the legalscope of the description is defined by the words of the claims set forthat the end of this disclosure. The detailed description is to beconstrued as exemplary only and does not describe every possibleembodiment since describing every possible embodiment would beimpractical, if not impossible. Numerous alternative embodiments couldbe implemented, using either current technology or technology developedafter the filing date of this patent, which would still fall within thescope of the claims.

It should also be understood that, unless a term is expressly defined inthis patent using the sentence “As used herein, the term ‘_(——————)’ ishereby defined to mean . . . ” or a similar sentence, there is no intentto limit the meaning of that term, either expressly or by implication,beyond its plain or ordinary meaning, and such term should not beinterpreted to be limited in scope based on any statement made in anysection of this patent (other than the language of the claims). To theextent that any term recited in the claims at the end of this patent isreferred to in this patent in a manner consistent with a single meaning,that is done for sake of clarity only so as to not confuse the reader,and it is not intended that such claim term be limited, by implicationor otherwise, to that single meaning. Finally, unless a claim element isdefined by reciting the word “means” and a function without the recitalof any structure, it is not intended that the scope of any claim elementbe interpreted based on the application of 35 U.S.C. §112, sixthparagraph.

Much of the disclosed functionality and many of the disclosed principlesare best implemented with or in software programs or instructions andintegrated circuits (ICs) such as application specific ICs. It isexpected that one of ordinary skill, notwithstanding possiblysignificant effort and many design choices motivated by, for example,available time, current technology, and economic considerations, whenguided by the concepts and principles disclosed herein will be readilycapable of generating such software instructions and programs and ICswith minimal experimentation. Therefore, in the interest of brevity andminimization of any risk of obscuring the principles and concepts inaccordance to the present invention, further discussion of such softwareand ICs, if any, will be limited to the essentials with respect to theprinciples and concepts of the preferred embodiments.

All patents and patent applications (including any patents which issuethereon) assigned to the Procter & Gamble Company referred to herein arehereby incorporated by reference to the extent that it is consistentherewith.

Absorbent Articles and Absorbent Materials

FIGS. 1A and 1B illustrate an example absorbent article 110, such as adiaper, a sanitary napkin, a pantiliner, an incontinent pad, a breastpad, a perspiration pad, and so on. FIG. 1A illustrates a partial aerialview of the example absorbent article 110, and FIG. 1B illustrates apartial cross section of the absorbent article. It will be recognizedthat the system and method of the present invention are not limited touse with standalone fully assembled absorbent articles, but could alsobe used for absorbent inserts and liners, e.g., a core assembly for adiaper. As used herein, the term “absorbent article” shall therefore beunderstood as referring to either a fully assembled article or anabsorbent component of an article.

The absorbent article 110 generally includes a liquid pervious topsheet120, a fluid impervious backsheet 130, both of which may be made ofnonwoven fabric, and an absorbent core 140 disposed between the topsheet120 and the backsheet 130. While the topsheet 120, the backsheet 130,and the absorbent core 140 may be assembled in a variety of well-knownconfigurations, various preferred configurations are described generallyin U.S. Pat. No. 5,554,145 entitled “Absorbent Article With MultipleZone Structural Elastic-Like Film Web Extensible Waist Feature” issuedto Roe et al. on Sep. 10, 1996; U.S. Pat. No. 5,569,234 entitled“Disposable Pull-On Pant” issued to Buell et al. on Oct. 29, 1996; andU.S. Pat. No. 6,004,306 entitled “Absorbent Article WithMulti-Directional Extensible Side Panels” issued to Robles et al. onDec. 21, 1999.

The absorbent core 140 may include an absorbent material 150 that isgenerally compressible, conformable, non-irritating to the wearer'sskin, and capable of absorbing and retaining liquids such as urine andother certain body exudates. The absorbent core 140 may include a widevariety of liquid-absorbent materials, including Absorbent GellingMaterials (AGM). AGM may be formed, for example, by superabsorbentpolymers, and AGM may include AGM granules (or particles) 160 that canswell upon contact with liquids, such as urine. While the AGM mayinclude AGM granules 160 of various sizes, shapes or forms, such asgranular, spherical, flakes, fibrous, etc., the AGM granules 160 areoften irregularly shaped particles, having a mean particle size of from10 μm to 1000 μm, typically with less than 5% by weight having aparticle size of less than 5 μm, and with less than 5% by weight havinga particle size of more than 1200 μm.

It will be understood by one of ordinary skill in the art that AGM andAGM granules 160 are used herein as just one example of an absorbentmaterial, and that the instant disclosure is not limited to AGM or toany particular absorbent material or materials. Examples of otherabsorbent materials include creped cellulose wadding; melt blownpolymers, including co-form; chemically stiffened, modified orcross-linked cellulosic fibers; tissue, including tissue wraps andtissue laminates; absorbent foams; absorbent sponges; or any other knownabsorbent material or combinations of materials. Example absorbentstructures for use as the absorbent assemblies are described in U.S.Pat. No. 4,610,678 (Weisman et al.); U.S. Pat. No. 4,834,735 (Alemany etal.); U.S. Pat. No. 4,888,231 (Angstadt); U.S. Pat. No. 5,260,345(DesMarais et al.); U.S. Pat. No. 5,387,207 (Dyer et al.); U.S. Pat. No.5,397,316 (LaVon et al.); and U.S. Pat. No. 5,625,222 (DesMarais etal.).

The AGM granules 160 may be distributed within the absorbent core 140 ofthe absorbent article 110 in a variety ways to form different patternsand shapes (including irregular shapes) both longitudinally (length wiseor x-directionally) and laterally (cross- or y-directionally), but alsoalong the thickness or caliper (or z-direction) of the absorbent article110. As explained in the background section, there may be variousreasons for arranging AGM granules 60 in a particular absorbent article10 in a special way, depending, for instance, on the nature and/or theintended use of the absorbent article 110. The present disclosure isdirected at providing techniques for evaluating the distribution of AGMgranules 160 in a given absorbent article.

AGM Distribution Evaluation Overview

FIG. 2 is a block diagram of an example AGM distribution evaluationsystem 200 for evaluating the distribution of AGM within an absorbentarticle. For example, the AGM distribution evaluation system 200 may beused to evaluate the distribution of AGM granules in absorbent articlessimilar to the absorbent article 110 illustrated in FIGS. 1A-1B. It willbe understood, however, that the AGM distribution evaluation system 200may be used to evaluate the distribution of AGM in other types ofabsorbent articles.

The AGM distribution evaluation system 200 includes one or more AGMdistribution imaging systems 205 coupled to one or more AGM distributionimage processing systems 240 (e.g., directly, via a network 250).Generally speaking, the AGM distribution imaging systems 205 representAGM distribution within absorbent articles 210 as image data 230, andthe AGM distribution image processing systems 240 generally process theimage data 230 to allow users to evaluate the AGM distribution withinabsorbent articles 210. For example, the AGM distribution imageprocessing systems 240 may simply display (e.g., on a computer screen)the distribution of AGM within a given absorbent article 210 as animage. Alternatively, or in addition, the AGM distribution imageprocessing systems 240 may provide various types of quantitative metricsto the user regarding the AGM distribution.

Details of AGM imaging and AGM image processing will be discussed inreference to FIGS. 3A-12. In particular, some example AGM distributionimaging systems 205 will be discussed in reference to FIGS. 3A-5, andexample AGM distribution image processing system 240 will be discussedin reference to FIGS. 6-10.

AGM Distribution Imaging

FIGS. 3A and 3B illustrate example AGM distribution imaging systems 305a and 305 b, respectively, that may be referred to collectively asexample AGM distribution imaging systems 305. The AGM distributionimaging systems 305 a and 305 b may be used as AGM distribution imagingsystems 205 illustrated in FIG. 2. However, it will be understood thatthe AGM distribution evaluation system 200 may utilize other AGMdistribution imaging systems 205. Furthermore, it will be appreciatedthat the AGM distribution imaging systems 305 a and 305 b may be usedwith systems and devices other than those illustrated in FIG. 2.

Generally speaking, the AGM distribution imaging system 305 includes oneor more radiation sources 375 that generate infrared radiation 370incident on an absorbent article 310 (oriented length-wise or width-wisewith respect to the Y-axis) and one or more detectors 380 on theopposite side of the absorbent article 310 that detect the infraredradiation 370 which passes through the absorbent core 340 of theabsorbent article 310. The wavelength range of the infrared radiation370 may be selected such that the infrared radiation 370 may besubstantially absorbed by the AGM granules 360 within the absorbent core340 of the absorbent article 310 but such that the infrared radiation370 may be substantially transmitted through other materials within theabsorbent article 310. In other words, the wavelength range of interestis one in which the infrared radiation 370 is more likely to be absorbedby the absorbent material than by other materials within the absorbentarticle. As a result, the concentration of AGM granules 360 within agiven region of the absorbent core 340 is related to the amount of theinfrared radiation 370 (within the wavelength range of interest) thatgets absorbed as it passes through that region.

In some embodiments, the wavelength range of interest may be between 3μm and 3.2 μm, as it has been observed that the absorbance of AGMgranules 360 within that wavelength range is higher than the absorbanceof other materials in the absorbent article 310 in that range.Accordingly, the radiation source 375 may include one or more sources ofinfrared radiation that transmit infrared signals through the absorbentarticle 310, and the detector 380 may include one or more infrareddetectors capable of detecting the infrared radiation within thewavelength range of interest on the opposite side of the absorbentarticle 310. More specifically, the detector 380 may observe the numberof photons that are transmitted through different regions of theabsorbent core 340. Those regions of the absorbent core 340 that includea higher concentration of AGM granules 360 may absorb more photons, andthose regions of the absorbent core 340 that include a lowerconcentration of AGM granules 360 may absorb fewer photons.

Based on the detected number of photons that pass through the differentregions of the absorbent core 340, the detector 380 may generate an AGMdistribution image 385, or data related thereto, that representspictorially the concentration of AGM granules 360 in the correspondingregions. In other words, the AGM distribution image 385 may represent atwo-dimensional spatial distribution of AGM granules 360 within theabsorbent core 340.

It should be noted that although the detector 380 is illustrated inFIGS. 3A-3B as a single element, the detector 380 may include multipledetector elements. For instance, in some embodiments, the detector 380may include an array of infrared detector elements.

In general, the distribution of AGM granules 360 in the various regionsof the absorbent article 310 may be represented in the AGM distributionimage 385 by the color depth in the corresponding region of the AGMdistribution image 385. In some embodiments, the color depth, or, moregenerally, the intensity of a pixel (or a group of pixels) within aparticular region of the AGM distribution image 385 may be related tothe number of photons transmitted through the corresponding region inthe absorbent core 340 and detected by the detector 380. For example, ifrelatively few photons are transmitted through a given region of theabsorbent core 340 and detected by the detector 380 (indicating arelatively high concentration of AGM granules 360), the pixels in thecorresponding region of the AGM distribution image 385 may be set to arelatively dark color. Likewise, if a relatively high number of photonsis transmitted through a given region of the absorbent core 340 anddetected by the detector 380 (indicating a relatively low concentrationof AGM granules 360), the pixels in the corresponding region of the AGMdistribution image 385 may be set to a relatively bright color.Accordingly, darker sections of the AGM distribution image 385 maycorrespond to regions within the absorbent core 340 having a higherconcentration of AGM granules 360, and lighter sections of the AGMdistribution image 385 may correspond to regions within the absorbentcore 340 having a lower concentration of AGM granules 360.

It will be appreciated by one of ordinary skill in the art that varioustypes of color palettes may be used for the AGM distribution image 385.In general, however, it may be useful to select a color palette thatcorresponds to the color depth perception of a human eye. That is, itmay be desired to generate an image with a granularity of color depththat a user is able to perceive. This may be achieved in a variety ofways, as discussed blow.

In the example AGM distribution imaging systems 305 a-b illustrated inFIGS. 3A and 3B, the AGM distribution image 385 is a binary (e.g.,black-and-white) image, where one color (e.g., black) indicatespresence, or a relatively high concentration, of AGM granules 360 andanother color (e.g., white) indicates absence, or a relatively lowconcentration, of AGM granules 360. In some embodiments, a threshold forthe number of received photons may be selected (e.g., 2170 photons perpixel) below which an AGM granule 360 is indicated to be present (andthe corresponding pixel or pixels are set to one color, e.g., black) andabove which an AGM granule 360 is indicated to not be present (and thecorresponding pixel or pixels are set to another color, e.g., white).

Additionally, or alternatively, the AGM distribution image 385 may be agrayscale (or monochrome) image, in which darker (but not necessarilyblack) sections generally indicate sections of relatively highconcentration of AGM granules 360 and brighter (but not necessarilywhite) sections 386 generally indicate sections of a relatively lowconcentration of AGM granules 360. A “gray-area” range in the number ofreceived photons may be determined (e.g., 2142 to 2397 photons perpixel), within which it may be unclear whether AGM granules 360 arepresent, but below which AGM granules 360 are indicated to be present,and above which AGM granules 360 are indicated not to be present.Consequently, if the number of received photons is lower than the lowerlimit of the determined gray-area range, the corresponding pixel orpixels may be set to black; if the number of received photons is higherthan the upper limit of the determined gray-area range, thecorresponding pixel or pixels may be set to white; and if the number ofreceived photons is within the determined gray-area range, thecorresponding pixel or pixels may be set to a grayscale levelcorresponding to the number of received photons relative to thegray-area range.

In some embodiments, the grayscale level corresponding to the number ofreceived photons relative to the gray-area range may be a linearfunction of the position within the range. For example, if the gray-arearange is between X and Y photons, and Z photons were received, thegrayscale level may be a linear function of quantities such as Z/(Y−X),(Y−X)/Z, and variations thereof. In some embodiments the grayscale levelmay increase by one level for each additional equal-sized group ofreceived photons. Accordingly, the color palette of the AGM distributionimage 385 may correspond to the gray-area range associated with thenumber of received photons.

It will be appreciated by one of ordinary skill in the art that thenumber of photons received by the detector 380 in different regions (andthe associated distribution of AGM granules 360) may be represented byvarious other types of AGM distribution images with a range of othercolor schemes. For example the AGM distribution image 385 may be acolorized grayscale image, or a false-color image, in which the numberof received photons may be mapped to a false color palette. The AGMdistribution image 385 may also be a sepia-tone image, a duotone, acyanotype, one of a range of possible monochrome images other than agray-scale image, etc., in which various visual indicators represent thecolor depth of the image. The AGM distribution image 385 may also be anyother type of a color image in which various color schemes may representthe color depth of the image and the corresponding distribution of AGMgranules 360. Still further, the AGM distribution image 385 maydistinguish presence of an AGM granule 360 (or a high concentrationthereof) from absence of an AGM granule 360 (or absence thereof) viavisual indicia, or a visual state, that is not related to color. Oneexample of such an indicia is concentration of particular characters(e.g., to represent high concentration of AGM 350).

Throughout the present disclosure, the terms “visual state” and “visualindicia” refer to an appearance which can be perceived by an unaidedhuman with normal vision. A visual state, or visual indicia, cangenerally include one or more colors, variations of color(s), patterns,letters, numbers, symbol, designs, images, and/or other visual devices.Colors include well known colors such as red, orange, yellow, green,blue, purple, etc. Variations of a color include variations in chroma,hue, and brightness, among others. While these informal terms are usedfor ease of reference, embodiments of the present disclosure areintended to encompass all colors which can be perceived by an unaidedhuman with normal vision.

As one example, an unaided human with normal vision should be able torecognize blue and yellow as different colors on sight. Thus, the blueand the yellow would be considered visually distinguishable visualstates or visual indicia. As another example, an unaided human withnormal vision may be able to recognize a light shade of orange and adark shade of orange as different shades of a color on sight. Thus, thelight shade of orange and the dark shade of orange would be consideredvisually distinguishable visual states of visual indicia. As a furtherexample, an unaided human with normal vision may be able to recognize afirst pattern and a second pattern as different visual states on sight.Thus, the first pattern and the second pattern would be consideredvisually distinguishable visual states.

As a still further example, an unaided human with normal vision shouldbe able to recognize an area with letters and a blank area as differentvisual states on sight. Thus, the area with letters and the blank areawould be considered visually distinguishable visual states. Similarly,an area with numbers, symbols, designs, images, and/or other visualdevices would also be considered visually distinguishable from a blankarea or from a uniformly colored area. In addition to these examples,there are many other possible visually distinguishable visual states, aswill be understood by one or ordinary skill in the art.

Referring again to FIGS. 3A-3B, it should be noted that unlikeconventional systems for evaluating the distribution of AGM 350 withinabsorbent articles 310, such as those systems that employ capacitivesensors, the example AGM distribution imaging systems 305 a-billustrated in FIGS. 3A and 3B may be used, in some embodiments, todetermine presence or absence of individual AGM granules 360. Moreover,because the image 385 representing the distribution of AGM granules 360may be stored in a digital format (e.g., bitmap, JPEG, TIFF, and so on),various image processing algorithms (e.g., implemented using computercode) may be used to determine a range of quantitative metricsassociated with the distribution of AGM granules 360 within an absorbentarticle 310, as will be subsequently described in more detail.

It should further be noted that the example AGM distribution imagingsystem 305 allows imaging of the distribution of AGM granules 360 withinan absorbent article 310 without physically altering the absorbentarticle 310 (e.g., cutting it open) and possibly altering the AGMdistribution within it. Consequently, as compared to existing systems,the example AGM distribution imaging system 305 provides a more accuraterepresentation of the distribution of AGM 350 within the absorbentarticle 310 in a non-destructive and non-disturbing manner.

Still further, it should be understood that the example AGM distributionimaging system 305 may be a stand-alone, e.g., offline, system, such asthe example AGM distribution imaging system 305 a illustrated in FIG.3A, but the example AGM distribution imaging system 305 may also be partof an inline product assembly system, such as the example AGMdistribution imaging system 305 b illustrated in FIG. 3B. As a result,the distribution of AGM granules 360 within the absorbent article 310may be imaged while the absorbent article is in motion, e.g., as itpasses through the AGM distribution imaging system 305 on an assembly,or a production line. Moreover, AGM distribution imaging may beperformed on multiple absorbent articles 310 as the absorbent articlesphysically move through the inline assembly system, both in assembledand in preassembled forms.

In an inline production environment, as illustrated in FIG. 3B, eachabsorbent article 310 may be imaged using the same or differentcombinations of radiation sources 375 and detectors 380. In someembodiments, a given absorbent article 310 may be imaged more than once,e.g., at different spatial orientations. In some cases, in order toachieve greater consistency across multiple absorbent articles 310, themultiple absorbent articles 210 that are imaged may be exposed toinfrared radiation from the radiation source 375 for approximately thesame amount of time. Alternatively, in some cases, it may be beneficialto expose different absorbent articles to infrared radiation fordifferent durations of time.

FIG. 4 is a block diagram of an example radiation source 475 that may beused to generate infrared radiation incident to an absorbent article inorder to evaluate the distribution of AGM within the absorbent article.The radiation source 475 may be used as the radiation source 375 inFIGS. 3A-3B. However, it will be understood that the AGM distributionimaging systems 305 a-b may use a different radiation source 375.Furthermore, although, for ease of explanation, FIG. 4 will be describedwith reference to FIGS. 1-3B, it will be understood that the exampleradiation source 475 may be utilized with systems, devices, andabsorbent articles other than those illustrated in FIGS. 1-3B.

The radiation source 475 may include a collection of light sources 410that generate infrared light 474. A number of different light sources410 may be used including those known in the art. Because it ispreferable that different AGM granules (e.g., inside a given absorbentarticle or inside different absorbent articles evaluated at differentpoints in time) be illuminated by similar radiation 470, it maygenerally be desired that these light sources 410 produce substantiallyuniform infrared light 474 over time. Additionally, or alternatively, itmay be preferable that the light sources 410 have adjustable level ofinfrared light 474, e.g., so that the light sources 410 may becalibrated if changes in time do occur, if their position and/ororientation is changed, and so on.

One example of a light source 410 that may produce substantially uniforminfrared light 474 over time and that may be adjustable is abroad-spectrum tungsten-halogen bulb. Generally speaking, atungsten-halogen bulb is an incandescent bulb in which a tungstenfilament is sealed into a compact transparent envelope filled with aninert gas and a small amount of halogen such as iodine or bromine. Thehalogen cycle increases the lifetime of the bulb and prevents itsdarkening by redepositing tungsten from the inside of the bulb back ontothe filament.

Because it may be of interest to evaluate the degree to which AGMgranules within different regions of an absorbent article absorb theinfrared light 474 produced by the light sources 410, such astungsten-halogen bulbs, it may further be desired that the material(e.g., glass) enclosing the tungsten filament does not substantiallyabsorb the produced infrared light 474. Accordingly, in someembodiments, it may be preferable to use tungsten-halogen bulbs thathave relatively thin glass structures enclosing the tungsten filament.

The light sources 410 may be arranged and generally operated in avariety of ways. For example, the light sources 410 may be arranged in atwo-dimensional pattern, such as a rectangular grid (e.g., roughly 26inches by 12 inches). The light sources 410 may also be arranged as astaggered array, or checkered, as illustrated in FIG. 4, to provide amore uniform distribution of the infrared light 474. In someembodiments, the light sources 410 may be operated between 4 and 24volts (e.g., 7 or 8 volts). The number of light sources 410 may vary,including 28, 50, 58, or any other number of different tungsten-halogenbulbs.

Because it is generally preferable that different AGM granules indifferent regions of the absorbent article be illuminated by similarradiation 470, at least within a spectrum of interest (e.g.,corresponding to wavelengths between 3 μm and 3.2 μm), it may further bedesired that the radiation source 475 scatter the light and producesubstantially uniform radiation 470 in space. Accordingly, in someembodiments, a diffuser assembly 424 may be used to generally diffusethe light 474 generated by the collection of individual light sources410 to produce a substantially uniform radiation 470 across theabsorbent article.

Various diffuser assemblies may be used in the radiation source 475. Forexample, the diffuser assembly 424 may include one or more (e.g., two)quartz diffusers 422 situated between the light sources 410 and theabsorbent article and oriented substantially parallel to the absorbentarticle and to the plane of the light sources 410, as illustrated inFIG. 4. One example of a suitable quartz diffuser 422 is the low O-Hquartz diffuser manufactured by Point Source Inc. of Germantown, Ohio,part number PSPG98745.

In some embodiments, the diffuser assembly 424 may include one quartzdiffuser 422 a close to the light sources 410 (e.g., less than an inchaway from the light sources), and another quartz diffuser 422 b fartheraway from the light sources (e.g., 4-6 inches away from the lightsources 410). Each quartz diffuser 422 may be made of GE 124 quartzmaterial and have a rectangular shape with a length of 25.7 inches, awidth of 11.4 inches, and a height (or thickness) of 0.118 inches.However, in some embodiments, or in some modes of operation, othermaterials, shapes and dimensions of the quartz diffusers 422 may besuitable. Also, more or fewer quartz diffusers 422 may be used.

FIG. 5 is a block diagram of an example detector 580 that may be used todetect infrared radiation 573 that passes through an absorbent articlein order to generate an image representing the distribution of AGMgranules within the absorbent article. The detector 580 may be used asthe detector 380 in FIGS. 3A-3B. However, it will be understood that theAGM distribution imaging systems 305 a-b may use a different detector380. Furthermore, while for ease of explanation FIG. 5 will be describedwith reference to FIGS. 1-4, it will be understood that the exampledetector 580 may be utilized with systems, devices, and absorbentarticles other than those illustrated in FIGS. 1-5.

The detector 580 includes a mid wave infrared (e.g., thermal) camera 510that is configured to detect infrared radiation 573 that passes throughan absorbent article, e.g., portion of the infrared ration 470 generatedby the radiation source 475 illustrated in FIG. 4 that is not absorbedby the absorbent article. As discussed above, the wavelength range ofthe infrared radiation 573 that is of particular interest is that withinwhich the infrared radiation 573 is absorbed by AGM granules, e.g.,infrared radiation 573 with wavelengths roughly between 3 and 3.2 μm.Accordingly, it may be desired that the mid wave infrared camera 510 beparticularly sensitive and responsive to infrared radiation within thatregion of 3 to 3.2 μm. Furthermore, because the mid wave infrared camera510 may be required to detect infrared radiation passing through anabsorbent article as the absorbent article is moving along, for example,an assembly line, it may further be desired that the mid wave infraredcamera 510 have a suitably high frame rate. An example of a suitable midwave infrared camera 510 would be an infrared camera that has asensitivity range between 3 μm and 5 μm and a frame rate of 120 framesper second for a 640×512 resolution and 424 frames per second for a305×256 resolution.

In addition to having the capability to detect infrared radiationpassing through an absorbent article and generating an imagerepresenting the distribution of AGM granules within that absorbentarticle, the mid wave infrared camera 510 may include one or morecommunication interfaces 535 to communicate image data 530, e.g., to anAGM distribution image processing system, such as the AGM distributionimage processing system 640 described below in reference to FIG. 6, ormore generally, to attached computers, remote servers and other devices.These communication interfaces 535 may include analog interfaces,digital interfaces, Gigabit Ethernet interfaces, and so on. The mid waveinfrared camera 510 may include additional components that, for ease ofexplanation, are not shown in FIG. 5, including those that are common,for example, to computing devices. For instance, the mid wave infraredcamera 510 may include memory storage space for storing the generatedAGM distribution images, various user interfaces to enable a user tointeract with the mid wave infrared camera 510, etc. The mid waveinfrared camera 510 may further include various software for dataacquisition, analysis, reporting, and so on.

One particular example of a suitable mid wave infrared camera 510 is theThermoVision® SC6000 infrared camera (“SC6000 camera”) manufactured byFLIR Systems, Inc. The SC6000 camera supports simultaneous andindependent analog and digital output data streams. The SC6000 cameraalso supports adjustable integration times (9 μs to full frame) andadjustable integration rates (120 frames per second for a 640×512resolution and 424 frames per second for a 305×256 resolution). Theframe rate is suitably high to make the SC6000 camera capable ofdetecting infrared radiation passing through an absorbent article whilethe absorbent article is moving along an assembly line, for instance.

It should be understood that the SC6000 camera is only one type of asuitable mid wave infrared camera 510. Other devices may be used todetect infrared radiation passing through an absorbent article and togenerate an image representing the distribution of AGM granules withinthat absorbent article, including various scanning devices, focal planearrays, linear arrays, line scans, and so on.

In addition to the mid wave infrared camera 510, the detector 580 mayinclude an optical band pass filter 524 for substantially blocking, orfiltering out, the infrared radiation that is outside the wavelengthrange of interest. For example, the optical band pass filter 524 maypass infrared radiation 576 that, if passed through AGM, would getsubstantially absorbed by AGM granules.

One example of a suitable optical filter 524 is an optical filtermanufactured by Barr Associates Inc. and sold under lot no.1105072016-2. This filter has a peak transmittance of 95.1% and aneffective span from 2.7581 to 3.3752 μm. Of course, other suitablefilters may be used.

AGM Distribution Image Processing

Referring again to FIG. 2, once an AGM distribution imaging system 205(such the AGM distribution imaging system described in reference toFIGS. 3-5) represents the AGM distribution of an absorbent article asAGM distribution image data 230, the AGM distribution image data 230 maybe communicated to one or more AGM distribution image processing systems240. An AGM distribution image processing system 240 may then processthe AGM distribution image data 230 to allow users to evaluate the AGMdistribution within the absorbent article 210.

FIG. 6 is a block diagram of an example AGM distribution imageprocessing system 640. The example AGM distribution image processingsystem 640 may be used as one of the AGM distribution image processingsystem 240 in the AGM distribution evaluation system 200 illustrated inFIG. 2. However, it will be understood that the AGM distributionevaluation system 200 may use other AGM distribution image processingsystem 240. Furthermore, for ease of explanation, the example AGMdistribution image processing system 640 will be described withreference to FIGS. 1-5. However, it will be understood that the exampleAGM distribution image processing system 500 may be utilized withsystems, devices, and absorbent articles other than those illustrated inFIGS. 1-5.

The AGM distribution image processing system 640 may include a number ofunits, or components. For example, AGM distribution image processingsystem 640 may include an image collector 650 for collecting image datafrom various AGM distribution imaging systems (e.g., the AGMdistribution imaging system 205 illustrated in FIG. 2 or the AGMdistribution imaging system described in reference to FIGS. 3-5) and animage database 660 for storing the image data. In order to interact withthe various AGM distribution imaging systems, the AGM distribution imageprocessing system 640 may further include a communication interface 670.Still further, the AGM distribution image processing system 640 mayinclude an AGM distribution image processing application 680 that isgenerally configured to process the collected AGM distribution imagedata and represent as output (e.g., via a user interface 690) qualityvalues associated with the distribution of AGM granules in absorbentarticles corresponding to that image data. In some embodiments, in orderto perform some of the image processing functions, the AGM distributionimage processing application 680 may interact with other applications,including those known in the art, such as the FLIR Software DevelopmentKit (SDK) manufactured by FLIR Systems, Inc., LabView manufactured byNational Instruments, Vision Builder for Automated Inspection (VBAI)manufactured by National Instruments, and various others.

It should be understood that the AGM distribution image processingsystem 640, in some embodiments, or in some modes of operation, may notinclude one or more of the units 650-680 described above or,alternatively, may not use each of the units 650, 660, 670, 680, 690 inprocessing AGM distribution image data. Furthermore, it will beappreciated that, if desired, some of the units 650, 660, 670, 680, 690may be combined, or divided into distinct units.

FIG. 7 is a flow diagram illustrating an example method 700 forprocessing AGM distribution image data using an AGM distribution imageprocessing system, such as the AGM distribution image processing system640 illustrated in FIG. 6. For ease of explanation, FIG. 7 will bedescribed with reference to FIGS. 1-6. It will be understood, however,that the example method 700 for processing AGM distribution image datamay be utilized with systems, devices and absorbent articles other thanthose illustrated in FIGS. 1-6.

Once an AGM distribution imaging system (such the AGM distributionimaging system described in reference to FIGS. 3-5) represents the AGMdistribution of an absorbent article as AGM distribution image data(block 705), the AGM distribution image processing system 640 may usethe communication interface 670, the AGM distribution image processingapplication 680, and/or the image collector 650 to receive, or retrievethe AGM distribution image data (block 710). If desired, the AGMdistribution image represented by the received AGM distribution imagedata may be displayed to the user (block 715) to allow the user toinspect the AGM distribution image visually and determine and/orevaluate various attributes of the AGM distribution within the absorbentarticle. Alternatively, or in addition, the AGM distribution imageprocessing application may be used to transform the AGM distributionimage data into one or more AGM distribution attribute values (block720).

For example, in some embodiments, the AGM distribution image processingapplication may be used to transform the AGM distribution image datainto one or more AGM distribution attribute values related to the shapeand/or pattern formed by the AGM granules (block 720 a). The AGMdistribution attribute values related to the shape and/or pattern formedby the AGM granules may be indicative of the perimeter, or the areawithin the absorbent core that is covered by the AGM granules.Additionally, or alternatively, the AGM distribution attribute valuesrelated to the shape and/or pattern formed by the AGM granules mayindicate the lengths of the different sides of the AGM pattern. The AGMdistribution attribute values related to the shape and/or pattern formedby the AGM granules may correspond to other metrics indicative of theshape and/or pattern formed by the AGM granules, such asperimeter-to-length ratios.

In some embodiments, the AGM distribution image processing applicationmay be used to transform the AGM distribution image data into one ormore AGM distribution attribute values related to the quantity of theAGM within the absorbent core of the absorbent article (block 720 b).For instance, the AGM distribution attribute values related to thequantity of the AGM may be indicative of the number of individual AGMgranules in the absorbent core. However, other quantity metrics (e.g.,surface area or volume covered by the AGM granules) may be used. Also,the AGM distribution attribute values related to the quantity of the AGMmay be indicative of the quantity of AGM within a particular region, orregions, within the absorbent core, or of the quantity of AGM within theabsorbent core as a whole.

In some embodiments, the AGM distribution image processing applicationmay be used to transform the AGM distribution image data into one ormore AGM distribution attribute values related to the density of the AGMwithin the absorbent core of the absorbent article (block 720 c).Similar to the AGM distribution attribute values related to the quantityof the AGM, the AGM distribution attribute values related to the densityof the AGM may be indicative of the density of AGM within a particularregion, or regions, within the absorbent core, or of the density of AGMwithin the absorbent core as a whole. For example, it may be desired totransform the AGM distribution image data into one or more AGMdistribution attribute values related to the density of the AGM withinregions that are more likely to come in contact with fluids.

In some embodiments, the AGM distribution image processing applicationmay be used to transform the AGM distribution image data into one ormore AGM distribution attribute values related to the evenness of theAGM within the absorbent core of the absorbent article (block 720 d).For example, AGM distribution attribute values related to the evennessof the AGM within the absorbent core of the absorbent article may beindicative of how uniformly the AGM granules are distributed within theabsorbent core, or within a particular region of the absorbent core.

In some embodiments, the AGM distribution image processing applicationmay be used to transform the AGM distribution image data into one ormore AGM distribution attribute values related to the AGM bias withinthe absorbent core of the absorbent article (block 720 e). For example,AGM distribution attribute values related to the AGM bias within theabsorbent core of the absorbent article may indicate whether there ismore AGM at the front of the absorbent article than in the back, on oneside than on another, in the center of the absorbent core than on theperiphery, and so on.

In some embodiments, the AGM distribution image processing applicationmay be used to transform the AGM distribution image data into one ormore AGM distribution attribute values related to density transitions inAGM within the absorbent article (block 720 f). For example, the AGMdistribution attribute values related to density transitions in AGMwithin the absorbent article may simply indicate existence of densitytransitions in AGM. Additionally, or alternatively, the AGM distributionattribute values related to density transitions in AGM within theabsorbent article may indicate the regions within the absorbent corewith density transitions in AGM and/or the rate of change in the densityof AGM in the various regions.

In some embodiments, the AGM distribution image processing applicationmay be used to transform the AGM distribution image data into one ormore AGM distribution attribute values related to presence of AGMislands within the absorbent article (block 720 g). Similarly, the AGMdistribution image processing application may be used to transform theAGM distribution image data into one or more AGM distribution attributevalues indicating regions within the absorbent core that have little orno AGM.

The AGM distribution image processing application may be used totransform the AGM distribution image data into one or more AGMdistribution attribute values related to various other attributes of thedistribution of AGM within the absorbent article (e.g., the degree ofscatter of the AGM granules). Alternatively, in some embodiments, theAGM distribution image processing application may be used to transformthe AGM distribution image data into only a subset of the AGMdistribution attribute values described above. Furthermore, it will beunderstood that the AGM distribution image processing application neednot transform the AGM distribution image data into one or more AGMdistribution attribute values in any particular order.

Once the AGM distribution image processing application transforms theAGM distribution image data into one or more AGM distribution attributevalues (block 720), the AGM distribution image processing applicationmay represent the AGM distribution attribute values as output (block730). For example, the AGM distribution image processing application maypresent the AGM distribution attribute values to the user, e.g., via auser interface, such as the user interface 690 illustrated in FIG. 6.Additionally, or alternatively, the AGM distribution image processingapplication may store the AGM distribution attribute values in a file,communicate the AGM distribution attribute values to other systems, andso on.

In some embodiments, the AGM distribution image processing applicationmay further transform the AGM distribution attribute values into one ormore AGM distribution quality values indicative of the quality of theAGM distribution within the absorbent article (block 735). Thus, the AGMdistribution image processing application may enable a user to determinethe quality of the AGM distribution within the absorbent article basedon one or more attributes of the AGM distribution within the absorbentarticle. For instance, the AGM distribution image processing applicationmay represent the AGM distribution quality values as output (block 740),e.g., by present the AGM distribution quality values to the user via auser interface (such as the user interface 690 illustrated in FIG. 6).Alternatively, the AGM distribution image processing application maypresent to the user only the AGM distribution attribute values (and notthe AGM distribution quality values), and the user may determine the AGMdistribution quality manually, e.g., by comparing the presented AGMdistribution attribute values to the desired AGM distribution attributevalues.

Evaluation of AGM Monolayer in an Absorbent Article

In some cases, the quality of the absorbent article, or an absorbentcomponent of an article yet to be fully assembled, may be related to thepresence of a monolayer of AGM granules within the absorbent core of theabsorbent article or within a particular region of the absorbentarticle. Accordingly, it may be, at times, desired to use an AGMdistribution evaluation system, such as the AGM distribution evaluationsystem 200 illustrated in FIG. 2 to characterize an AGM monolayer and toevaluate the AGM monolayer in absorbent articles.

FIGS. 8A and 8B illustrate an example absorbent article 810, such as adiaper, a sanitary napkin, a pantiliner, an incontinent pad, a breastpad, a perspiration pad, and so on, that includes an AGM monolayer 850in the absorbent core 840. FIG. 8A illustrates a partial aerial view ofthe example absorbent article 810, and FIG. 8B illustrates a partialcross section of the absorbent article 810.

Generally speaking, an article (such as the absorbent article 810) issaid to include an AGM monolayer when the article includes a surfacethat is substantially covered by at least one layer of AGM granules 860,but not necessarily more than one AGM granule 860 over any of thesurface area. The AGM monolayer within an absorbent article 810 maytherefore substantially ensure, or make it highly likely, that thetopsheet 820 and the backsheet 830 of the absorbent article 810 do notcome in contact with each other. More particular requirements as to whatconstitutes an AGM monolayer 850 (e.g., spacing of adjacent AGM granules860, minimum number of AGM granules per unit of surface area, and so on)may depend on various factors, such as the nature and/or the intendeduse of the absorbent article.

FIG. 9 is a flow diagram illustrating an example method 900 forevaluating the AGM monolayer of an absorbent article using an AGMdistribution evaluation system, such as the AGM distribution evaluationsystem 200 illustrated in FIG. 2. For ease of explanation, FIG. 9 willbe described with reference to FIGS. 1-8. It will be understood,however, that the example method 900 for evaluating the monolayer of anabsorbent article may be utilized with systems, devices and absorbentarticles other than those illustrated in FIGS. 1-8.

In some embodiments, in order to characterize the monolayer, a targetarticle that includes a monolayer of AGM granules may be provided tosimulate an absorbent article with an AGM monolayer (block 910). Variousattributes of the target article may then be determined, and themonolayer may be characterized based on these variables.

FIG. 10 illustrates an example target article 1000 that may be used tocharacterize the monolayer. The target article 1000 includes an AGMmonolayer 1010, e.g., a surface that is substantially covered by AGMgranules 1060 The target article 1000 may also include one or morelayers (e.g., two layers) of nonwoven fabric 1020, or other materialthat may simulate the topsheet and the backsheet of an absorbentarticle.

As explained below, the monolayer of the target article may becharacterized using infrared radiation of a particular wavelength rangeof interest (e.g., 3-3.2 μm), within which the infrared radiation ismore likely to be absorbed by the absorbent material than by othermaterials within the target article. Therefore, it may be desired thatthe target article 900 not include any materials (other than the AGMgranules 960) that substantially block infrared radiation within thatwavelength range. Because sapphire does not substantially block infraredradiation in that wavelength range, a sapphire slide covered with AGMgranules 960 and wrapped in nonwoven fabric 920 is one example of asuitable target article 900. However, it will be appreciated by one ofordinary skill in the art that other target articles may be used.

Referring again to FIG. 9, an AGM distribution imaging system, such asthe AGM distribution imaging systems 305 a-b illustrated in FIGS. 3A and3B, may be used to generate image data indicative of the absorbance ofthe target article within the wavelength range of interest (block 920).As explained in reference to FIGS. 3A and 3B, a radiation source (suchas radiation source 375) may transmit infrared radiation throughdifferent regions the target article, and a detector (such as thedetector 380) may detect how much of that radiation was transmittedthrough each region of the target article. In particular, the detectormay detect the number of photons transmitted through each region.

In some embodiments, in order to verify that the target article wasassembled properly (block 930), various statistical checks may beperformed on the generated data indicative of the absorbance ofdifferent regions of the target article. For example, it may be verifiedthat the maximum detected number of photons (corresponding to a regionwith minimum absorbance) is within three standard deviations of theaverage detected number of photons across all regions. If so, the targetarticle was assembled properly (“YES” branch of block 930). Otherwise(“NO” branch of block 930), a new target article may be provided (block910).

If the target article was assembled properly (“YES” branch of block930), the generated data regarding the absorbance of the target articlemay be used to evaluate the distribution of AGM in absorbent articles.For example, when imaging absorbent articles, the maximum detectednumber of photons transmitted through a region of a target article maybe used as a threshold. A value below this threshold may indicate thatan AGM granule is present, and a value above this threshold may indicatethat an AGM granule is not present. The maximum detected number ofphotons transmitted through a region of a target article may also beused as the center of the “gray-area” range and/or of the color palettefor an AGM distribution image, as described in reference to FIGS. 3A-3B.

Still further, if the target article was assembled properly (“YES”branch of block 930), the generated data regarding the absorbance of thetarget article may be used to evaluate the quality of the absorbentarticle. For example, the AGM distribution imaging system may be used togenerate data indicative of an absorbance of infrared radiation withinthe wavelength range of interest incident on the absorbent article(block 940), and that data may be compared with the data related to theabsorbance of the target article. In particular, the detector may detectthe number of photons transmitted through each region of the absorbentarticle. If the detector detects that a certain region of the absorbentarticle transmitted more photons than the maximum detected number ofphotons transmitted through the target article, this may be anindication that the there is a “hole” in the AGM monolayer of theabsorbent article, that an AGM monolayer is not present in the absorbentarticle, or that the AGM monolayer is of relatively poor quality, etc.If on the other hand, there are no regions in the absorbent article thattransmitted more photons than the maximum detected number of photonstransmitted through the target article, this may indicate that theabsorbent article has an acceptable AGM monolayer. Therefore, generally,the quality of the AGM monolayer in the absorbent article may bedetermined by comparing the disparity between data related to theabsorbance of the assembled target article and data related to theabsorbance of the absorbent article (block 950).

The quality of the AGM monolayer in the absorbent article may berepresented as output (960). This may be done in a variety of ways. Forexample, quality of the AGM monolayer may be quantified and presented asa value, e.g., via a user interface. Alternatively, various types ofvisual indicia indicative of the quality of the AGM monolayer may bepresented to the user. It will be understood that may other techniquesof representing the quality of the AGM monolayer in the absorbentarticle as output may be used.

Several example techniques for imaging and evaluating the distributionof an absorbent material in an absorbent article have been describedabove in terms of particular embodiments. However, other embodiments arepossible. For example, various pre-processing steps, such as smoothing,binarization, thinning, and minutiae detection may be included invarious embodiments to enhance the effectiveness of the techniquesdescribed above.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this disclosure.

What is claimed is:
 1. A method of evaluating quality of an absorbentmaterial, the method comprising: using infrared imaging to generate dataindicative of an absorbance of infrared radiation within a particularwavelength range incident on a target article, the target articlecomprising a monolayer of absorbent material substantially covering asurface of the target article, and wherein the infrared radiation withinthe particular wavelength range is more likely to be absorbed by theabsorbent material than by other materials within the target article;using infrared imaging to generate data related to an absorbance ofinfrared radiation within the particular wavelength range incident on anabsorbent core of an absorbent article; and determining a quality of theabsorbent article based on a disparity between the data related to theabsorbance of infrared radiation within the particular wavelength rangeincident on the target article and the data related to the absorbance ofinfrared radiation within the particular wavelength range incident theabsorbent core of the absorbent article.